The reduced number of Spaniards facilitated the maintenance of a comparative independence by these as yet unconquered Indians, at the same time that it facilitated the flight of those who, having bent their necks to the yoke, found it unbearably heavy. According to "Regidor" (Prefect) Hernando de Mogollon's letter to the Jerome fathers, fully one-third of the "pacified" Indians--that is, of those who had submitted--had disappeared and found a refuge with their kinsmen in the neighboring islands. The first fugitives from Boriquén naturally did not go beyond the islands in the immediate vicinity. Vieques, Culébras, and la Mona became the places of rendezvous whence they started on their retaliatory expeditions, while their spies or their relatives on the main island kept them informed of what was passing. Hence, no sooner was a new settlement formed on the borders or in the neighborhood of some river than they pounced upon it, generally at night, dealing death and destruction wherever they went. In vain did Juan Gil, with Ponce's two sons-in-law and a number of tried men, make repeated punitive expeditions to the islands. The attacks seemed to grow bolder, and not till Governor Mendoza himself led an expedition to Vieques, in which the cacique Yaureibó was killed, did the Indians move southeastward to Santa Cruz. That the Caribs[31] inhabiting the islands Guadeloupe and Dominica made common cause with the fugitives from Boriquén is not to be doubted. The Spaniard was the common enemy and the opportunity for plunder was too good to be lost. But the primary cause of all the so-called Carib invasions of Puerto Rico was the thirst for revenge for the wrongs suffered, and long after those who had smarted under them or who had but witnessed them had passed away, the tradition of them was kept alive by the areytos and songs, in the same way as the memory of the outrages committed by the soldiers of Pizarro in Peru are kept alive _till this day_ among the Indians of the eastern slope of the Andes. The fact that neither Jamaica nor other islands occupied by Spaniards were invaded, goes to prove that in the case of Puerto Rico the invasions were prompted by bitter resentment of natives who had preferred exile to slavery, coupled, perhaps, with a hope of being able to drive the enemies of their race from their island home, a hope which, if it existed, and if we consider the very limited number of Spaniards who occupied it, was not without foundation. * * * * * It was Nemesis, therefore, and not the mere lust of plunder, that guided the Boriquén Indians and their Carib allies on their invasions of Puerto Rico. Diego Columbus during his visit in 1514 had founded a settlement with 50 colonists along the borders of the Daguáo and Macáo rivers on the eastern coast.